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Hiroyuki Yamamoto

Publications and source records attributed to Hiroyuki Yamamoto.

At least 55 records · Page 3Linked to original sources
PubMed2005

Novel synthesis, static and dynamic properties, and structural characteristics of 5-cyano[n](2,4)pyridinophane-6-ones (n= 9-6) and their chemical transformations.

A novel synthesis of 5-cyano[n](2,4)pyridinophane-6-ones 12a-d (n= 9, 8, 7, and 6) consists of allowing cyanoacetatoamide to react with cycloalk-2-enones. Their static and dynamic properties as well as structural characteristics are studied on the basis of their spectroscopic properties, cyclic voltammetry, and theoretical calculations. The (1)H and (13)C NMR spectra at various temperatures have clarified the dynamic behavior of the methylene chains for [7](2,4)- and [6](2,4)pyridinophane-6-one derivatives 12c and 12d. The energy barrier (Delta G(++)) of the bridge flipping of 12c is estimated to be 12.0 kcal mol(-1)(T(c)= 0 degree C). On the other hand, compound 12d undergoes pseudorotation (conformational change of the methylene chain) at room temperature, and does not undergo bridge flipping even at 150 degree C in DMSO-d(6). The energy barrier (Delta G(++)) of the pseudorotation of the methylene chain 12d of is found to be 10.5 kcal mol(-1)(T(c)=-25 degree C), and thus, two stable conformers of the hexamethylene bridge of 12d are determined as predicted by theoretical calculations. Deformation of the pyridone ring of 12d is also determined by X-ray crystallographic analysis. Furthermore, chemical transformations of 12a-c leading to 5-carbamoyl[n](2,4)pyridinophanes 15a-c are also accomplished successfully in moderate to good yields.

Journal Article↗
PubMed2005

A case of POEMS syndrome with cystoid macular edema.

PURPOSE: To introduce a case of POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome with bilateral cystoid macular edema (CME). DESIGN: Interventional case report. METHODS: Temporal changes of serum vascular endothelial growth factor (VEGF) levels and macular thickness were evaluated. RESULTS: A 53-year-old woman with POEMS syndrome was referred complaining of long-standing impaired vision. Typical CME demonstrating petal-like dye pooling was observed in both eyes. After subtenon administrations of triamcinolone acetonide (TA), pars plana vitrectomy, and intraocular TA injection in the right eye, macular thickness decreased. Intraocular VEGF levels were <31 pg/ml at the vitrectomy and intraocular TA injection, whereas serum the VEGF level was >2000 pg/ml throughout the follow-up periods. In the untreated left eye, macular thickness altered related to serum VEGF level. CONCLUSIONS: Based on the low intraocular VEGF level and serum VEGF-related change of macular thickness, elevated serum VEGF might be a cause of CME in POEMS syndrome.

Female↗
PubMed2005

Two cases of reversible posterior leukoencephalopathy syndrome, one with and the other without pre-eclampsia.

Two cases of reversible posterior leukoencephalopathy syndrome (RPLS) are reported. One was a 26-year-old woman, who had pre-eclampsia and developed cortical blindness and subsequent eclampsia at 28 weeks' gestation. The other was a 27-year-old woman, who had no pre-eclampsia and developed loss of consciousness and subsequent systemic convulsion at 36 weeks' gestation. On brain magnetic resonance imaging, they both had high signal intensity on T2-weighted and fluid-attenuated inversion recovery images, and normal signal intensity on diffusion-weighted image of the posterior lobe, which almost disappeared with the amelioration of clinical symptoms thereafter. RPLS is considered to be the result of vasogenic brain edema caused by hypertension. Two hypotheses are conceived to explain the emergence of RPLS without hypertension. The first suggests that an immunotolerant condition such as pregnancy can easily cause vasogenic edema without the elevation of blood pressure. The second suggests that hypertension exists but cannot be detected because it is extremely acute and transient.

Adult↗
PubMed2005

Successful treatment of primary cardiac lymphoma with atrioventricular nodal block.

A 69-year-old female suffering from third-degree atrioventricular block with syncope underwent permanent pacemaker implantation. However, she developed shortness of breath 2 months after the implantation. Blood tests revealed elevated levels of LDH, CRP, BNP, and SIL-2R. Transthoracic echocardiography showed thickened left and right atrial walls with mild pericardial effusion. A diagnosis was made based on a CT scan and histology. Although most primary cardiac malignant lymphomas are associated with a poor prognosis, the patient was treated successfully with chemotherapy.

Aged↗
PubMed2005

[A case of Mikulicz's disease complicated by autoimmune pancreatitis, in which impaired glucose tolerance was improved by glucocorticoid treatment].

A 73-year-old woman had experienced dry mouth and swellings of both upper eyelids from 1998. In October 2003, she also developed bilateral submandibular swellings, and was diagnosed with diabetes mellitus and prescribed antidiabetic medication. She consulted our hospital in the summer of 2004 due to the exacerbation of eyelid swelling, and was admitted in October 2004. Keratoconjunctivitis sicca was not present. CT and MRI of the head showed bilateral enlargement of the lacrimal and submandibular glands. Serological investigations revealed hypergammaglobulinemia, but as antinuclear antibody and anti-SS-A antibody were absent, further investigation was performed. Serum concentrations of IgG4 were elevated and biopsy of the minor salivary gland revealed a severe infiltration of IgG4-positive plasmacytes. The patient was therefore diagnosed with Mikulicz's disease. Abdominal CT demonstrated diffuse pancreatic swelling, and endoscopic retrograde cholangio-pancreatography revealed stricture of the common bile duct and main pancreatic duct, suggesting the complication of autoimmune pancreatitis. Treatment was commenced with 40 mg/day of prednisolone. This resulted in rapid resolution of the lacrimal and submandibular gland swellings and recovery of salivary gland function. Diffuse swelling of the pancreas and stricture of the common bile duct and main pancreatic duct also improved, and endogenous insulin secretion increased. Both Mikulicz's disease and autoimmune pancreatitis presented with elevated serum IgG4 and infiltration of IgG4-expressing plasma cells into the glandular tissues. We recently proposed the new diagnostic entity of "IgG4-related plasmacytic exocrinopathy"; however, if diabetes mellitus in autoimmune pancreatitis was caused by direct dysfunction of pancreatic cells, we must reconsider this pathogenesis and consider a wider concept including exocrine as well as endocrine glands. This case, in which both types of glands were affected, is therefore of considerable interest.

Aged↗
PubMed2005

[An adult case of congenital fiber type disproportion (CFTD) with cardiomyopathy].

A 30 year-old man with CFTD was reported. He had normal motor milestone during infancy but had been poor at sports. At 28, he experienced exertional and nocturnal dyspnea and had been diagnosed as having dilated cardiomyopathy. At 29, a cardiac pace-maker was implanted because of the complete atrio-ventricular block. Around that time, he began to notice limb muscle weakness. Examination at 30 showed mild diffuse muscle atrophy and weakness at the torso and limbs. No dysmorphic features or joint contractures were noted. His serum CK was normal. A histochemical study of his muscle biopsy showed type 1 fiber predominancy (64.6%) and that the mean diameter of type 1 fibers was smaller than that of type 2 by 14.6% (36.9 microm vs. 42.3 microm). Results of immunostaining of dystrophin, emerin, laminA/C, alpha, beta, gamma, delta-sarcoglycan or dysferlin were normal. He was diagnosed as having CFTD because there were no histochemical abnormalities which characterize other congenital myopathies except for the type 1 predominancy and atrophy.

Adult↗
PubMed2004

Relationship between cerebral injury and inflammatory responses in patients undergoing cardiac surgery with cardiopulmonary bypass.

This study was performed to evaluate whether cytokines, adhesion molecules, ghrelin and S-100B are useful markers in predicting the cerebral infarction after cardiac surgery with cardioplumomary bypass (CPB). The patients (n=20) were classified into two groups; group A (n=4) showed postoperative organized cerebral damage, while group B (n=16) consisted of patients without occurrence of postoperative strokes. Before CPB, serum levels of S-100B in both groups A and B were low (<0.5 ng/mL), while ghrelin concentrations in group A (all patients had history of strokes) were much higher than those in group B. After CPB, when serum levels of S-100B in group A at 24h were higher than those in group B, ghrelin in group A at same time point showed high levels in comparison to group B. At 12 and 24h after CPB, levels of tumor necrosis factor (TNF)-alpha, interleukin-10 and soluble TNF-receptor I in group A were significantly higher than those in group B. In conclusion, it is considered that ghrelin as well as S-100B can be a useful marker for the prediction of stoke after CPB. Increase of TNF-alpha, interleukin-10 and soluble TNF-receptor I after CPB may be involved in the pathogenesis of stroke after CPB.

Aged↗
PubMed2004

Interplay of insulin-like growth factor-II, insulin-like growth factor-I, insulin-like growth factor-I receptor, COX-2, and matrix metalloproteinase-7, play key roles in the early stage of colorectal carcinogenesis.

PURPOSE: The aim of this study was to characterize the relationship of insulin-like growth factor (IGF)-II expression with IGF-I, IGF-I receptor (IGF-IR), cyclooxygenase-2 (COX-2), and matrix metalloproteinase (MMP)-7 in early colorectal carcinogenesis. EXPERIMENTAL DESIGN: With the semiquantitative reverse transcriptase-PCR, 90 human colorectal tumor tissues (63 adenomas and 27 submucosal pT1 cancers) were analyzed for IGF-II, IGF-IR, IGF-I, COX-2, and MMP-7 expression. Ninety-nine adenoma tissues and 60 pT1 cancer tissues were also analyzed immunohistochemically for IGF-II expression. Loss of imprinting of the IGF-II gene was analyzed. Paired carcinoma and adenoma tissues obtained from a carcinoma in adenoma lesion was analyzed by a cDNA array. RESULTS: IGF-II mRNA expression was detected in 37.8% of the 90 colorectal tumor tissues. The frequency of IGF-II mRNA expression was significantly higher in pT1 cancer (70.4%) than in adenoma (23.8%). Immunohistochemical IGF-II expression was also more frequently detected in pT1 cancer (58.3%) than in adenoma (25.3%). Loss of imprinting of the IGF-II gene was observed in 15 (44.1%) of the 34 colorectal tumors in which IGF-II was overexpressed. IGF-II expression was positively correlated with the expression of IGF-IR and IGF-I. COX-2 and MMP-7 mRNA expression was detected in 42.2% and 77.8% of the tumor tissues, respectively, and both were positively correlated with IGF-I, IGF-II, and IGF-IR expression. IGF-II was the most differentially expressed gene between carcinoma and adenoma lesions. CONCLUSIONS: IGF-II, in conjunction with IGF-IR, IGF-I, COX-2, and MMP-7, seems to play a key role in the early stage of colorectal carcinogenesis.

Adenocarcinoma↗
PubMed2004

A case of colorectal carcinoma in adenoma analyzed by a cDNA array.

PATIENT AND METHODS: A 68-year-old woman presenting with bloody stools and anemia was referred to our hospital. Colonoscopy showed a Is-type tumor of 45 mm in diameter in the cecum and three Is-type tumors in the ascending colon. Ileocecal resection with regional lymph node dissection was performed. Microscopically, the large tumor consisted of a well-differentiated adenocarcinoma with a tubulovillous adenoma (TVA) component (carcinoma in adenoma). Some carcinoma (CA) cells had invaded the submucosal layer, but the lymph nodes were negative for malignancy. The other three polyps were diagnosed as TVAs. Because her family history fulfilled the Amsterdam criteria II for hereditary non-polyposis colorectal cancer (HNPCC), genetic analysis was performed. All of the four tumor tissues were classified as microsatellite stable (MSS) according to the National Cancer Institute guideline for analysis of microsatellite instability (MSI). K-ras mutation was detected in both CA and TVA lesions of the carcinoma in adenoma. To clarify relevant alterations of gene expression associated with adenoma-carcinoma progression, the gene expression profiles of these tumor tissues were analyzed by a cDNA array. RESULTS: Although the gene expression profiles were similar, insulin-like growth factor-II (IGF-II) was expressed most differentially in CA and TVA tissues. The results were further substantiated by comparison of the gene expression profiles of CA and TVA lesions of the carcinoma in adenoma. CONCLUSION: The results suggest that overexpression of IGF-II played an important role in the progression of adenoma to carcinoma in this patient.

Adenocarcinoma↗
PubMed2004

The receptor tyrosine kinase Ror2 associates with and is activated by casein kinase Iepsilon.

Ror2, a member of the mammalian Ror family of receptor tyrosine kinases, plays important roles in developmental morphogenesis, although the mechanism underlying activation of Ror2 remains largely elusive. We show that when expressed in mammalian cells, Ror2 associates with casein kinase Iepsilon (CKIepsilon), a crucial regulator of Wnt signaling. This association occurs primarily via the cytoplasmic C-terminal proline-rich domain of Ror2. We also show that Ror2 is phosphorylated by CKIepsilon on serine/threonine residues, in its C-terminal serine/threonine-rich 2 domain, resulting in autophosphorylation of Ror2 on tyrosine residues. Furthermore, it was found that association of Ror2 with CKIepsilon is required for its serine/threonine phosphorylation by CKIepsilon. Site-directed mutagenesis of tyrosine residues in Ror2 reveals that the sites of phosphorylation are contained among the five tyrosine residues in the proline-rich domain but not among the four tyrosine residues in the tyrosine kinase domain. Moreover, we show that in mammalian cells, CKIepsilon-mediated phosphorylation of Ror2 on serine/threonine and tyrosine residues is followed by the tyrosine phosphorylation of G protein-coupled receptor kinase 2, a kinase with a developmental expression pattern that is remarkably similar to that of Ror2. Intriguingly, a mutant of Ror2 lacking five tyrosine residues, including the autophosphorylation sites, fails to tyrosine phosphorylate G protein-coupled receptor kinase 2. This indicates that autophosphorylation of Ror2 is required for full activation of its tyrosine kinase activity. These findings demonstrate a novel role for CKIepsilon in the regulation of Ror2 tyrosine kinase.

3T3 Cells↗
PubMed2004

Association of matrilysin-2 (MMP-26) expression with tumor progression and activation of MMP-9 in esophageal squamous cell carcinoma.

Expression of matrilysin-2, matrix metalloproteinase (MMP)-26, has been implicated in the progression of several types of human cancer. Matrilysin-2 has been reported to be a physiological and pathological activator of pro-MMP-9. The aim of this study was to examine matrilysin-2 expression and determine whether it is correlated with progression of human esophageal squamous cell carcinoma (ESCC). Semi-quantitative reverse transcriptase-polymerase chain reaction, immunohistochemical analysis, zymography and an in vitro invasion assay were performed. Matrilysin-2 mRNA expression was undetectable or only faintly detected in non-tumor tissues, but its overexpression was detected in 24 of the 50 ESCC tissues. Matrilysin-2 overexpression was significantly correlated with depth of invasion, lymph node metastasis and an advance in pathological tumor node metastasis (pTNM) stage. Sections with immunostaining signals in >10% of carcinoma cells at the invasive front, which were observed in 46 of 100 cases, were judged to be positive for matrilysin-2 expression. Matrilysin-2 expression was significantly correlated with depth of invasion, lymph node and distant metastasis, advance in pTNM stage and recurrence. Expression of matrilysin-2 was significantly correlated with nuclear beta-catenin expression and MMP-9 expression. Patients with matrilysin-2-positive cancer had significantly shorter overall and disease-free survival periods than did those with matrilysin-2-negative cancer. Matrilysin-2 expression retained its significant predictive value for overall and disease-free survival in multivariate analysis. Moreover, patients with concomitant expression of matrilysin-2 and MMP-9 had the worst prognosis. Zymography revealed that matrilysin-2 expression was significantly correlated with expression of active MMP-9 in ESCC tissues. Matrilysin-2-transfected TE-1 ESCC cells showed active MMP-9 activity and were more invasive in vitro compared with mock-transfected TE-1 cells. The results of this study suggest that matrilysin-2, the expression of which is closely correlated with nuclear beta-catenin expression and active MMP-9 activity, plays a key role in the progression of ESCC.

Adenocarcinoma↗